There was a perfect Marco Rubio moment in the last Republican debate days before the Iowa caucuses on Tuesday.
"Let's talk about electability," began the Fox News moderator, Bret Baier, addressing Rubio alone as he stood among his fellow candidates – except Donald Trump, who had boycotted the event for some perceived offence from Fox.
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"Time magazine once called you 'the Republican saviour'. [Right-wing talk radio host] Rush Limbaugh and others said you likely will be president someday."
In response Rubio went the full Rubio.
"There's only one saviour and it's not me," he began, fixing Baier with that intense, cherubic gaze, his voice a hymn of urgent sincerity.
"It's Jesus Christ who came down to Earth and died for our sins and so I've always made that clear about that cover story."
("Cover story", he said, just in case you missed that detail in the framing the question.)
You could almost hear Iowan evangelical Christians – and there are an election-winning heap of them – swoon across the state as Rubio spoke.
Indeed swoon is a term you often hear associated with Rubio.
"When Marco Rubio speaks, young women swoon, old women faint and toilets flush themselves," Dan Gelber, a prominent Democratic politician in Rubio's home state of Florida once told colleagues, The New Yorker recently reported.
Three nights later Senator Ted Cruz beat the favourite Trump, but the story of the night was Rubio's surge. He smashed all expectations to secure 23 per cent of the vote, just a single percentage point behind Trump.
And so the swooning broke out again. This time it was the Republican establishment and sympathetic media. For months the GOP and its donor class have stood by helpless as Trump and Cruz hijacked their primary election, sweeping aside all the candidates they had expected to dominate the race – men like Jeb Bush, Scott Walker, John Kasich and Chris Christie.
Fear and loathing turned to outright panic after Christmas when it started to dawn on them that one of these two outsiders might win the nomination and stuff up their plans for the presidential election.
Finally though Rubio appeared to have broken away from the pack of second-tier candidates and taken the fight to Cruz and Trump. This was a man they could work with, a man who could even beat Hillary Clinton – the candidate they expect to face – in the November presidential election.
The party elders did not fall in behind Rubio when he launched his campaign last year because it was not his turn.
Rubio, now 44, was a freshman senator from Florida who had been mentored by Jeb Bush, and this was Bush's year. Everyone said so. The party elders said so and so did donors, who poured $US100 million ($140 million) into Bush's campaign in the opening weeks in a bid to warn off other challengers.
But outside the party dispassionate observers always thought Rubio was a likely contender. All last year PredictWise, which aggregates polling and betting market data, considered Rubio to be the eventual Republican nominee.
And it is not so hard to see why, especially when you compare Rubio's perceived strengths and weaknesses with Jeb Bush's and Clinton's. By simply appearing on stage he makes the case for generational change. As a Cuban American he is a rebuke to those who claim that the Republican Party has become the last redoubt for angry white America.
Marco Rubio: 'I am grateful to you, Iowa'
Republican candidate Marco Rubio thanks supporters in Iowa, vowing to be back next year as president.
He is articulate and charismatic in public, smart and nimble in debate, engaged and compelling in his Senate committee work. And where Bush seems to sometimes bore even himself on the hustings, pure ambition shivers about Rubio's person.
He might not enjoy the benefits of the Bush family's enormous political machine, but nor is he encumbered by the legacy of George W. Bush's disastrous invasion of Iraq.
Unlike both Bush and Clinton, Rubio is free of the taint of dynasty.
Rubio by inclination, by resume and by circumstance, appears to straddle the divides that have torn apart his party.
He is a product of both the Tea Party revolution that swept the nation after the election of Barack Obama and the Republican establishment of Florida.
There are those though who worry that he might too easily shift from one shape to the next. As he moves onto the centre stage of the Republican campaign, this mercurial quality of Rubio's is coming into sharper focus.
Rubio burst onto the national political stage in 2010 when he won a Senate seat that party elders had set aside for a former governor.
In his victory speech he declared: "No matter where I go or what title I may achieve, I will always be the son of exiles."
Rubio understood America's greatness, he said, because the nation had given a home to millions of Cubans who fled Fidel Castro's regime in Cuba and let them prosper in freedom.
It was a year or so before investigative reporters discovered this was not quite true, even though it was the story that Rubio had always told as he made his way up through the ranks in Florida.
The Washington Post managed to dig up the Rubio family's naturalisation papers. It turned out his family had arrived in the US two years before Castro took power.
This meant the family had fled the Batista regime, not Castro's. To understand the significance about this you need to know a little about Florida politics.
Cuba's exile community settled around Miami after the revolution and soon dominated local politics. After that the community spread its reach and took power in the State House in Tallahassee. This gave them outsized power in Washington DC, because Florida is the largest swing state in the nation. Their significance was amplified by Cuba's central role in the Cold War.
But the Cubans who shaped Miami's politics were exiles of Castro, rather than economic refugees of Batista's Cuba.
This had political and class implications. The exiles tended to be richer, whiter, more reliably conservative.
When this contradiction was revealed Rubio said he had simply misunderstood the family's oral history.
"I don't buy that and no one buys that," Alfredo Jose Estrada, editor of Latino magazine, told Politico recently. "We know when we left and why. To the day and to the minute and what we took with us and what fit into that suitcase. It's part of the Cuban exile mythology. It defines us as Cuban exiles."
In America Rubio's parents worked hard in low-paid jobs and eventually prospered. Rubio himself recalls being an indifferent high school student, but he became politically active early. As a 21-year old student he volunteered in the office of the Cuban-American state senator Lincoln Diaz-Balart during his first Congressional race and in 1996 as a law graduate Rubio found work in a law firm run by Bush ally Al Cardenas, a central figure in the Cuban-American political scene.
By 2000 Rubio landed a seat in the Florida House of Representatives and graduated, in Gelber's words, from being a foot soldier to a lieutenant in the army of then governor Jeb Bush.
As a representative Rubio became known for his efforts to soften tough state anti-immigration legislation, and for his energetic and creative gerrymandering while serving on a boundaries committee.
He built on his close relationship with Bush, who in 2005 presented him with a ceremonial sword and anointed him as the next Speaker of the House, the first Cuban American to hold that position.
"I'm going to bestow to you the sword of a great conservative warrior," he said, as a crowd of Republican faithful cheered.
In 2010 he fought the former Florida governor for a vacant Senate seat. During this contest Rubio abandoned his progressive immigration stances to fall in line with the prevailing hardline mood among the nascent far-right Tea Party movement.
It worked, and upon his victory the Weekly Standard, the journal of the neoconservative movement, anointed him as the important incoming conservative.
A recent New Yorker profile of him entitled The Opportunist notes that one Latino activist group ran a campaign the motto "No Somos Rubios" (We're not Rubios).
But even this position was to change again. Shocked by the party's second loss to Obama in the 2012 presidential race Republican strategists identified the party's poor standing among America's Latino community as a long-term existential threat.
For the first time in a generation it appeared there was significant bipartisan support for sweeping immigration reform that would include a "pathway to citizenship" for the estimated 11 million undocumented immigrants living in the US.
Rubio spied a way to attach his name to significant legislation and joined the so-called "gang of eight" Congress members championing the package.
It didn't work out. A wave of unaccompanied children driven from their homes due to gang violence in central America hit the southern border fuelling right-wing fears of a tide of unregulated immigration, even though statistics showed undocumented movement across the border to be at near record lows.
Ted Cruz harnessed the anger and led a campaign against the reform that swept up the angry Republican base. Rubio dropped the reform and has been distancing himself from it ever since.
In matters of faith though Rubio has found himself more in line with the insurgent right. Baptised a Catholic; Rubio abandoned the Church as a teenager to become a Mormon when his family moved for a time to Nevada, before returning to it as a young man.
These days he attends an evangelical Protestant service on Saturdays and a Catholic Mass on Sundays. He has been an outspoken opponent of abortion, including in cases of rape and incest,
Though he presents himself as an agent of generational change, Rubio's politics in Congress have proved to be more in line with the recent past. His policies are largely in line with George W. Bush's, but more to the right.
Rubio soon secured a seat on the Senate foreign relations committee – a plum post for a man wanting to establish himself as a presidential contender. On the committee he has been a consistent voice in support of Israel's Likud government and for aggressive US military action in both the Middle East and Ukraine, positions that place him firmly within the neoconservative movement.
He has taken policy advice from champions of the Iraq War, including the Weekly Standard editor William Kristol and another leading neocon intellectual, Robert Kagan.
Rubio advocates cutting the number of tax brackets from seven to two and reducing the tax rate for those in the higher tier. According to Politifact the effect would be to direct 55 per cent of all new income gains to the top 20 per cent of Americans.
In keeping with current Republican orthodoxy he would abolish the Affordable Care Act, rejects action on climate change and is steadfastly opposed to any form of gun control.
Despite the clear evidence of his overwhelming ambition, Rubio's announcement last April that he was standing for president raised eyebrows.
Bush had been his mentor, and now the Cuban-American political machine in Florida was going to have to take sides.
"Marco was a bright young man, at a time when no Cuban Americans had been elected, Jeb was our ambassador. Jeb was our ombudsman with Washington from early on. People don't forget that ... You could say that anyone in office in Florida today from their 30s to their 60s has a debt to Jeb Bush," the regional kingmaker Al Cardenas told Politico.
Many stuck by Bush at first, but Jeb's campaign has caused despondency.
In the early debates the two were wary of attacking one another. Rubio stuck to constant reminders that he was the future rather than direct assaults on his mentor.
That time has passed, and when they have tussled recently, Rubio has won.
In one recent debate exchange Bush limply condemned Rubio for failing to attend key Senate votes while campaigning for the presidential nomination.
Bush watched awkwardly as Rubio demolished him before a cheering audience.
"The only reason you're [attacking me] is because we're running for the same position. Someone convinced you attacking me is going to help you," he said.
As Trump began to surge in polls last summer Republican elders reassured themselves that the infatuation with the showman would blow itself out.
It never did. Trump continued to soar through autumn and winter and Bush's numbers slipped from low double to single digits. He failed to crack 3 per cent support in Iowa.
As the decline continued serious attention began to quietly shift to Rubio. He assiduously courted big donors like Sheldon Adelson, the casino magnate concerned with smashing union power and entrenching support for Israel, and the Koch brothers, the industrialists who champion deregulation and shackling of the Environmental Protection Agency.
Rubio is now said to be winning what are known as the Adelson and Koch primaries.
He has secured more endorsements from fellow members of Congress than any other candidate – a measure that is often a telling predictor of the eventual nomination outcome.
The Clinton camp is watching with trepidation.
"There is no question that Rubio is the Republican that Democrats fear most," the former White House communications director Dan Pfeiffer wrote for CNN.
"He is a skilled messenger and could very credibly run a change v more of the same campaign against Clinton.
"Rubio is also the most broadly appealing GOP candidate and would have the best shot to close the non-white vote gap with the Democrats."
A December MSNBC/Telemundo/Marist poll found that Clinton led when matched against all the Republican candidates, but her margin against Rubio – three points among all voters, 19 points among Latinos – was the lowest.
Tuesday's New Hampshire primary has become critical. Trump is still streets ahead in the polls and is expected to win. Rubio is now leading Cruz though.
And if the party's establishment candidates – Bush, Kasich and Christie – are to survive to fight on into the spring, they are going to have to do far better than they did in Iowa.
If they don't pressure will begin to mount for them to fall in behind Rubio.
It is hard to imagine how Bush feels about his former protege, but it is clear that Rubio is wasting little time thinking of the feelings of his political godfather.
Days after Rubio announced he was standing reporters asked him whatever happened to the sword that Bush had once bestowed upon him with such ceremony, the one he had hung with evident pride on his office wall.
"I have it somewhere at home," he responded vaguely. "I have young kids. I don't want them to run around with a sword."